From 756bc0a4cadee75a22564ac82be69312c86b5f77 Mon Sep 17 00:00:00 2001
From: Dan Fuhry <dan@fuhry.com>
Date: Sat, 14 Mar 2026 19:34:49 -0400
Subject: [PATCH] [sd] add AddressUpdate type for easier stringification

---
 grpc/internal/client/client.go  |  6 +++---
 grpc/internal/client/dns_srv.go |  4 ++--
 sd/watcher.go                   | 20 +++++++++++++++-----
 3 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/grpc/internal/client/client.go b/grpc/internal/client/client.go
index 990e7c7..c7ce9d3 100644
--- a/grpc/internal/client/client.go
+++ b/grpc/internal/client/client.go
@@ -25,7 +25,7 @@ type Client interface {
 type ClientOption = option.Option[*client]
 
 type AddressProvider interface {
-	GetAddrs(context.Context) ([]sd.ServiceAddress, error)
+	GetAddrs(context.Context) (sd.AddressUpdate, error)
 }
 
 type client struct {
@@ -38,10 +38,10 @@ type client struct {
 }
 
 type staticAddressProvider struct {
-	addresses []sd.ServiceAddress
+	addresses sd.AddressUpdate
 }
 
-func (s *staticAddressProvider) GetAddrs(_ context.Context) ([]sd.ServiceAddress, error) {
+func (s *staticAddressProvider) GetAddrs(_ context.Context) (sd.AddressUpdate, error) {
 	return s.addresses, nil
 }
 
diff --git a/grpc/internal/client/dns_srv.go b/grpc/internal/client/dns_srv.go
index 00241e9..eedd375 100644
--- a/grpc/internal/client/dns_srv.go
+++ b/grpc/internal/client/dns_srv.go
@@ -14,13 +14,13 @@ type dnsSrvAddressProvider struct {
 
 var _ AddressProvider = &dnsSrvAddressProvider{}
 
-func (d *dnsSrvAddressProvider) GetAddrs(context.Context) ([]sd.ServiceAddress, error) {
+func (d *dnsSrvAddressProvider) GetAddrs(context.Context) (sd.AddressUpdate, error) {
 	results, err := dns.ResolveSRV(d.serverId.Name(), "grpc", constants.SDDomain)
 	if err != nil {
 		return nil, err
 	}
 
-	var sdAddrs []sd.ServiceAddress
+	var sdAddrs sd.AddressUpdate
 	for _, r := range results {
 		sdAddrs = append(sdAddrs, sd.ServiceAddress{
 			Hostname: r.Hostname,
diff --git a/sd/watcher.go b/sd/watcher.go
index 9b57c07..e43e859 100644
--- a/sd/watcher.go
+++ b/sd/watcher.go
@@ -28,7 +28,7 @@ type SDWatcher struct {
 	lock         *sync.RWMutex
 	wg           *sync.WaitGroup
 	results      []ServiceAddress
-	watchers     chan []ServiceAddress
+	watchers     chan AddressUpdate
 	watcherCount int
 }
 
@@ -45,6 +45,8 @@ type ServiceAddress struct {
 	key string
 }
 
+type AddressUpdate []ServiceAddress
+
 func (w *SDWatcher) init() error {
 	if w.Region == "" {
 		w.Region = "dns"
@@ -68,7 +70,7 @@ func (w *SDWatcher) init() error {
 	}
 
 	if w.lock == nil {
-		w.watchers = make(chan []ServiceAddress, 10)
+		w.watchers = make(chan AddressUpdate, 10)
 		w.starter = &sync.Once{}
 		w.lock = &sync.RWMutex{}
 		w.wg = &sync.WaitGroup{}
@@ -78,7 +80,7 @@ func (w *SDWatcher) init() error {
 	return nil
 }
 
-func (w *SDWatcher) GetAddrs(ctx context.Context) ([]ServiceAddress, error) {
+func (w *SDWatcher) GetAddrs(ctx context.Context) (AddressUpdate, error) {
 	err := w.init()
 	if err != nil {
 		return nil, err
@@ -150,9 +152,9 @@ func (w *SDWatcher) publishResults(kvs map[string][]byte) {
 	}
 }
 
-func (w *SDWatcher) WatchUpdates(ctx context.Context) chan []ServiceAddress {
+func (w *SDWatcher) WatchUpdates(ctx context.Context) chan AddressUpdate {
 	w.watcherCount++
-	och := make(chan []ServiceAddress)
+	och := make(chan AddressUpdate)
 
 	go (func() {
 		defer func() { w.watcherCount-- }()
@@ -233,3 +235,11 @@ func (sa ServiceAddress) ToURI() *url.URL {
 		Path:   fmt.Sprintf("/%s", sa.Protocol.String()),
 	}
 }
+
+func (au AddressUpdate) String() string {
+	out := fmt.Sprintf("%d addrs:\n", len(au))
+	for i, a := range au {
+		out += fmt.Sprintf("  addr %d: hostname=%q ip4=%q ip6=%q node=%q port=%d protocol=%q service=%q shard=%q\n", i, a.Hostname, a.IP4, a.IP6, a.Node, a.Port, a.Protocol, a.Service, a.Shard)
+	}
+	return strings.TrimSpace(out)
+}
-- 
2.52.0